An aroma of sage filled the air as Christina Mulcahy and her two sons toiled in the morning sunshine uprooting invasive plants from a hill at the Hal Brown Park at Creekside. The family removed fistful after fistful of bermudagrass from around sage brush and coyote bush plants, giving the native vegetation space to grow.

"It's hard work, but it's worth it to see it all pretty and healthy," Mulcahy said.

Mulcahy was one of 10 volunteers participating in the clean up at the Kentfield park Saturday. Members of Save The Bay, an organization that restores Bay Area habitats, organized the event in partnership with the Marin County Parks and Open Space District as part of an ongoing effort to protect the brackish marsh near the park. The organizations have been teamed up for about a year, holding 10 events to remove non-native plants, plant native ones and gather litter at the site — the only one in Marin County that Save The Bay helps maintain.

Kirk Schroeder, a Marin County Parks ranger and site supervisor, said volunteers have put nearly 800 hours of work into keeping the stretch of land between the marsh and the hill that leads up to the park clean. Without the community's help, he said the county would be forced to use herbicide or a tractor to remove unwanted plants, both of which have their drawbacks.

"We don't have the staff to manage this type of area by hand," Schroeder said. "What we're doing is very tedious work."

Volunteers circled plants on their hands and knees, removing fast-spreading grasses and placing cardboard covered with mulch around desired bushes. The heat and lack of sunshine inflicted by the cardboard will kill off unwanted grasses and seeds.

Jon Backus, Save The Bay restoration project specialist, said it's important to protect the marsh because it's home to two endangered species; the clapper rail and the salt marsh harvest mouse, which is endemic to the Bay Area. When the tide rises in the marsh, these critters head for cover from prey in the area volunteers were tidying.

Backus said the marsh is a special community asset, especially since it used to be a less pleasant area to visit.

"This was really used as a dumping ground for dredging from the Corte Madera Creek in the 1970s," Backus said, adding that neighbors later stepped up to protect the marsh when plans were afoot to fill it with soil and build houses.

Having lived in Kentfield for 15 years just down the street from the marsh, Mulcahy said it's important for her to help protect the place she and her family have enjoyed year after year. She said it's also crucial to pass along that message to her children.

"I want them to appreciate where we live," she said.

While not thrilled about being awoken early on the Saturday morning before school starts at Kent Middle School to do hard labor, 13-year-old Matthew Mulcahy said at least time goes by fast when weeding.